Lise Meitner and the Atomic Bomb
By discovering how to split an atom, she also figured out how to make a massive explosion in a short period of time. When an atom splits it releases three fast moving neutrons which in turn divide more atoms until there are no more atoms to split. As that happens the neurons and their energy have no where to go, so it explodes, resulting in massive destruction. Lise Meitner never wanted to use her discovery for weapons of mass destruction, but her discovery helped found the bomb of the modern world. Below is a quick video on how atomic bombs work and how split atoms make it all happen.
Unfortunately, against Meitner's wishes, atomic bombs were not only successful, but many countries around the world began developing them, launching them on each other, and testing new ones between the years of 1945 and 1998. Below is a video showing all the nuclear bombs dropped, tested, and exploded in the span of the 53 years of nuclear bomb frenzy.